On Decaying Counterflow Turbulence in He II
On Decaying Counterflow Turbulence in He II
复制标题
He II 中的衰变逆流湍流
DOI：
10.1007/s10909-006-9270-0
复制
发表时间：
2005
影响因子：
2
通讯作者：
L. Skrbek
中科院分区：
文献类型：
--
作者：
C. Barenghi;L. Skrbek
我们回顾了现有的实验和数值数据衰减逆流湍流在他II和目前我们的理解的基础物理。我们考虑到温度梯度存在于稳态逆流湍流，在早期阶段的衰变的湍流仍然是热驱动的事实，以及在开始的衰变的涡旋纠缠强烈极化的事实。当产生逆流湍流的加热器被关闭时，涡旋缠结衰减，涡旋线随机化它们的空间取向，并且缠结的偏振减小。去极化过程减慢了测量涡线密度的横向二次声波信号的恢复;在某些参数值下，它甚至导致横向二次声波的振幅在达到有限尺寸通道中典型的经典均匀各向同性湍流的普遍−3/2幂时间律衰减之前净减小。
We review available experimental and numerical data on decaying counterflow turbulence in He II and present our current understanding of the underlying physics. We take into account the temperature gradient present in the steady-state counterflow turbulence, the fact that in the early stage of the decay the turbulence is still thermally driven, and the fact that at the beginning of the decay the vortex tangle is strongly polarized. When the heater that generates the counterflow turbulence is switched off, the vortex tangle decays, the vortex lines randomize their spatial orientation and the tangle’s polarization decreases. The process of depolarization slows down the recovery of the transverse second sound signal which measures the vortex line density; at some values of parameters it even leads to a net decrease of the amplitude of the transverse second sound prior to reaching the universal −3/2 power temporal law decay typical of classical homogeneous isotropic turbulence in a finite-sized channel.